Question

我创建一个名为“value_array”的变量然后它将arraylist的值放入其中变成那样：value_array = collection.get（0）; 然后我尝试通过Toast功能显示结果结果是：Value_1 = 1 然后我退出了入队功能当我尝试使用Toast功能时结果是：Value_1 = 0 调用相同变量的解决方案是什么，在函数外部以免丢失其值，看看我的代码：

package com.example.cca.retrofit;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.Toast;

import java.util.ArrayList;
import java.util.List;
import retrofit.Call;
import retrofit.Retrofit;
//https://github.com/metachris/retrofit2-samples
//https://www.youtube.com/watch?v=uAXn7VntQvw

public class MainActivity extends AppCompatActivity {

    //HttpApiSimple asd;
    private Call<List<Users>> getUsersCall;
    private Call<HttpApi.HttpBinResponse>call;
   // private List<int[]> collection;
    private List<Integer>collection;
    private HttpApi api;
    public int value_array;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        // asd = new HttpApiSimple();
        testInstance();
    }

    private void testInstance(){

       api = HttpApi.getInstance();
       value_array = 0;
       api.addHeader("Authorization","MyT23");
        /// Get iteme from index number33333+69

        getUsersCall = api.getService().getAllChatRooms();
        getUsersCall.enqueue(new retrofit.Callback<List<Users>>(){
            @Override
            public void onResponse(retrofit.Response<List<Users>> response, Retrofit retrofit){
                collection = new ArrayList<>();

                for(int i=0; i<response.body().size(); i++){

                     collection.add(Integer.parseInt(response.body().get(i).id));
                 }

                 value_array = collection.get(1);
                 // Add pramater from another table ;
                // Toast.makeText(MainActivity.this,"Value_1=" + value_array ,Toast.LENGTH_LONG).show();

                call = api.getService().postWithJson(new HttpApi.LoginData(13,"Rauool",value_array));
                call.enqueue(new retrofit.Callback<HttpApi.HttpBinResponse>(){
                    @Override
                    public void onResponse(retrofit.Response<HttpApi.HttpBinResponse> response, retrofit.Retrofit retrofit){
                        // Toast.makeText(MainActivity.this, "" + response.body().message.toString(), Toast.LENGTH_LONG).show();
                    }
                    @Override
                    public void onFailure(Throwable t) {
                        //    Toast.makeText(MainActivity.this, "" + t.toString(), Toast.LENGTH_LONG).show();
                    }
                });
            }

            @Override
            public void onFailure(Throwable t){
                //    Toast.makeText(MainActivity.this," " + t.toString() ,Toast.LENGTH_LONG).show();
            }});
    }

}

Answer 1

它不会“丢失”。您没有看到初始值（或默认值为0）的原因是您进行异步调用以获取value_array的值。当呼叫处于待处理状态时，您的代码仍会执行，并在收到结果之前继续生成Toast。

您的案例无需修复。只需删除

Toast.makeText(MainActivity.this,"Value_2 = " + value_array,Toast.LENGTH_LONG)

因为它没有任何价值。您有两种回调方法onResponse和onFailure。在那里，你可以随着结果收到你想做的任何事情。

变量在函数外失去了它的值？

1 个答案: